How to Build a Garage Attic

Structure

• The structure for a garage attic is comprised of the trusses that support the roof, the garage walls and a floor over the garage ceiling joists. Most garages with peaked roofs, therefore, already have the basic structural components needed to accommodate an attic. Likewise, a garage without a peaked roof will require new trusses and an entirely new roof to add space for an attic. Work with a builder to determine the best plan for adding an attic.

Construction Process

• If your garage already has roof trusses and ceiling joists, you can build an attic yourself. Use plywood sheets to construct the attic floor, attaching them with nails to the top of the ceiling trusses. Leave an opening for a hatch that will allow access via a ladder, or with pull-down stairs that mount between joists.

  Adding a garage attic also involves insulating the space to retain heat, to prevent ice dams on the garage roof and to keep your stored items safe from moisture. The attic provides a convenient place to inspect the underside of your roof, so you can caulk any gaps and add foam insulation between trusses.

Attic Apartments

• Adding an attic apartment to your garage is somewhat more complicated than adding an attic for storage. The new living space will alter your home's square footage measurement, boost your property taxes and require a building permit. You'll also need to hire professionals to install plumbing and electrical wiring to provide the apartment with the necessary fixtures. Finishing the space with drywall, which you can attach directly to the roof trusses and garage wall studs, will give it a polished look and make it habitable.

Lofts

• A loft provides another option for adding attic storage to an existing garage space. Lofts are open storage areas that usually only occupy a portion of a garage's upper level. Garage lofts may be low enough to access with a step ladder, or high enough to park cars beneath. Adding a loft requires new structural supports that suspend the loft from roof trusses or ceiling joists. This leaves the space below the loft open for parking or additional storage.